Nonwoven composite

ABSTRACT

The application relates to a nonwoven composite containing a lofty nonwoven layer and a film. The lofty nonwoven layer contains a plurality of primary fibers and defines a plurality of peak regions and a plurality of valley regions. The film contains a thermoplastic polymer and has a peak film thickness in the peak regions of the layer. The film is present on at least a majority of the second surface of the nonwoven layer. Within the valley regions, the film encapsulates a plurality of fibers from the nonwoven layer. The cross-sectional area fraction of total fibers in the film within the valley regions is at least about 8% and the cross-sectional area fraction of total fibers in the film within the peak regions is less than about 5%.

FIELD OF THE INVENTION

The present invention generally relates to composites having soundabsorbing properties and methods of making and using such composites.

BACKGROUND

Sound absorbing materials are used in a number of applications withinthe transportation, building and construction, office and homefurnishing, and entertainment industries to enhance user experiences andreduce unwanted noise. Composite materials offer the opportunity to tunethe acoustic properties of sound absorbing materials for optimalperformance in specific applications while minimizing the overall partmass. In many of these applications it is also required that thematerial be molded into a specified shape and rigidity. In theautomotive industry, these types of moldable acoustic compositematerials are often used for applications such as wheel well liners,underbody shields, hood liners, firewall barriers, dash insulators, andflooring among others. In certain automotive applications, thesemoldable acoustic composite materials may require an aestheticallypleasing cover material be incorporated into the part.

There is a need for moldable acoustic nonwoven composite materialshaving improved and tailored acoustic properties, while retaining lowmaterial and manufacturing costs.

BRIEF SUMMARY

The application relates to a nonwoven composite containing a loftynonwoven layer and a film. The lofty nonwoven layer contains a pluralityof primary fibers and has a first side and an opposite second side. Thesecond side defines a plurality of peak regions and a plurality ofvalley regions. The first side and the second side further define anonwoven layer thickness. The film contains a thermoplastic polymer andhas a peak film thickness in the peak regions of the layer. The film ispresent on at least a majority of the second side of the nonwoven layer.Within the valley regions, the film contains a plurality of encapsulatedfibers from the nonwoven layer. The cross-sectional area fraction oftotal fibers in the film within the valley regions is at least about 8%and the cross-sectional area fraction of total fibers in the film withinthe peak regions is less than about 5%. In one embodiment, the film hasa first porosity in the valley regions and a second porosity in the peakregions, where the first porosity is greater than the second porosity.

The application also relates to a process for forming a nonwovencomposite. The process includes forming a lofty nonwoven layercontaining a plurality of primary fibers and having a first side and anopposite second side, the first side and the second side furtherdefining a nonwoven layer thickness. The process includes obtaining athermoplastic polymer and applying the thermoplastic polymer to thesecond side of the nonwoven layer, where the thermoplastic polymer is inthe form of a molten polymer, semi-molten polymer, or solid film. Next,pressure and optionally heat is applied to the nonwoven layer andthermoplastic polymer, where the thermoplastic polymer and the secondside of the nonwoven layer are subjected to a textured surface forming aplurality of peak regions and a plurality of valley regions in thesecond side of the nonwoven layer and encapsulating a portion of thefibers from the nonwoven layer into the thermoplastic polymer within thevalley regions. The cross-sectional area fraction of total fibers in thefilm within the valley regions is at least about 8% and thecross-sectional area fraction of total fibers in the film within thepeak regions is less than about 5%. The thermoplastic polymer is cooledforming a thermoplastic film and the nonwoven layer which together formthe nonwoven composite. In one embodiment, the composite is subjected toadditional heat and optionally pressure such that a plurality of poresform in the thermoplastic film within the valley regions. This causesthe thermoplastic film to have a first porosity in the valley regionsand a second porosity in the peak regions, where the first porosity isgreater than the second porosity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cross-section of one embodiment of the nonwovencomposite.

FIG. 2 is a micrograph of the cross-section of one embodiment of thenonwoven composite.

FIG. 3 illustrates a cross-section of one embodiment of the nonwovencomposite after an additional heat cycle.

FIG. 4A is a top-view micrograph of one embodiment of the nonwovencomposite. FIG. 4B is a top-view micrograph of one embodiment of thenonwoven composite after an additional heat cycle.

FIG. 5 is a micrograph of the cross-section of one embodiment of thenonwoven composite after an additional heat cycle.

DETAILED DESCRIPTION

The present disclosure is directed to moldable acoustic composites thatprovide acoustical properties including, but not limited to, soundabsorption properties and sound barrier properties. The acousticcomposite (and the acoustically coupled nonwoven composites within theacoustic composite) have exceptional sound absorption properties; (2)have structural features that enable their use in a variety ofapplications; and (3) can be manufactured in a cost-effective manner.

Referring to FIG. 1, there is shown a cross-sectional illustration ofone embodiment of the nonwoven composite 10. The nonwoven composite 10contains two main elements, a lofty nonwoven layer 100 and athermoplastic film 200. The nonwoven composite has an upper surface 10 aand a lower surface 10 b. The distance between these two surfaces is thenonwoven composite thickness.

The lofty nonwoven layer has a first side 100 a and a second side 100 b.The distance between the first side 100 a and the second side 100 b isdefined as the nonwoven layer thickness. Typically, the first side 100 aof the nonwoven layer 100 forms the upper surface 10 a of the composite10. In one embodiment, the first side 100 a of the nonwoven layer 100forms the “A” layer surface, meaning the outermost exposed and visiblesurface.

The lofty nonwoven layer 100 may be formed by any suitable methodincluding, but not limited to carding or garneting, air laying,cross-lapping, needling, structuring, stitching, and bonding. Thenonwoven layer 100 contains a plurality of primary fibers as well asoptional fibers such as binder fibers and other effect fibers.

Preferably, the lofty nonwoven layer 100 is formed by carding,cross-lapping, and needle-punching, and optionally thermal bonding aplurality of primary fibers and optional binder fibers. The nonwovenlayer preferably has a thickness between about 1 and 25 mm and morepreferably a thickness between about 1 and 8 mm. The nonwoven layerpreferably has an areal density of between about 100 and 2000 g/m² andmore preferably between about 250 and 800 g/m². In one embodiment, thenonwoven layer is substantially and generally uniform in fiber weightpercentages, areal weights, and areal densities across the nonwovenlayer. In one embodiment, the primary fibers are in an amount greaterthan about 50% by weight of the nonwoven layer 100, preferably betweenabout 60 and 100% by weight of the nonwoven layer, and more preferablybetween about 70 and 95% by weight of the nonwoven layer.

The primary fibers of the lofty nonwoven layer 100 are fibers thatprovide mass and volume to the material. The primary fibers providevolume or bulk or loft in the Z-direction. For the purposes of thisapplication, the Z-direction of the nonwoven is defined as the directionorthogonal to the planar direction of the nonwoven layer. The planardirection means in a plane parallel to the first and second sides of thenonwoven layer. The primary fibers are preferably staple fibers. Primaryfibers can include virgin and recycled fibers, high crimp fibers,hollow-fill fibers, non-circular cross-section fibers and other commonstaple fibers. Some examples of primary fibers include polyester,polypropylene, nylon, cotton, and wool as well as other staple fibers.In a preferred embodiment, the primary fibers comprise polyester.Preferably, the primary fibers have a denier of approximately 1 to 20,more preferably 1.5 to 12 denier, and most preferably 3 to 9 denier. Inone embodiment, the fibers have a circular cross section. In anotherembodiment, fibers have higher surface area or noncircular cross sectionsuch as segmented pie, 4DG, winged fibers, tri-lobal etc. It has beenshown that the fiber denier, crimp, and cross-section have an effect onthe sound absorption properties of the nonwoven.

In addition to the primary fibers 110 in the lofty nonwoven layer 100,the optional binder fibers of the lofty nonwoven layer 100 are fibersthat adhere to and bond with the other fibers. Binder fibers can includefibers that are heat activated. Examples of heat activated binder fibersare fibers that can melt at lower temperatures, such as low melt fibers,bi-component fibers, such as side-by-side or core and sheath fibers witha lower sheath melting temperature, and the like. In one embodiment, thebinder fibers are a polyester core and sheath fiber with a lower melttemperature sheath. A benefit of using a heat activated binder fiber asthe binder fiber in the lofty nonwoven layer 100, is that the layer canbe subsequently molded to part shapes for use in automotive floors,wheel well liners, underbody shields, hood liners, engine compartmentcovers, ceiling tiles, office panels, etc. Another benefit of binderfibers in the lofty nonwoven layer when the first side 100 a is anexposed “A” surface is to increase the abrasion resistance of theexposed nonwoven layer. The binder fibers are preferably staple fibers.Preferably, when the nonwoven composite 10 is subjected to an additionalheat cycle and then cooled forming the composite 20, the binder fibersremain as discernable fibers. In another embodiment, when the nonwovencomposite 10 is consolidated, the binder fibers lose their fiber shapeand form a coating on surrounding materials. When activated by heat orother means, the binder fibers create fused bond points or welds betweenadjacent fibers that create a network of interconnected fibers.Preferably, the optional binder fibers have a denier less than or aboutequal to 15 denier, more preferably less than about 6 denier, and mostpreferably 4 denier or less.

In one embodiment, the first side 100 a of the lofty nonwoven layer 100is formed into a random velour. To create the random velour, the loftynonwoven layer is passed over a brush apparatus having a series ofprojections and interstices between the projections. The lofty nonwovenlayer is then needled from the second side 100 b of the lofty nonwovenlayer into the brush apparatus such that a portion of the primary fibersare pushed into the interstices of the brush apparatus and out of andaway from the first side 100 a side of the lofty nonwoven layer. Thiscreates a loop-like and velour-like surface on the first side 100 a ofthe lofty nonwoven layer 100. This random velour look is desirable aswhen used as an “A” surface (the surface of the composite accessible inthe final application) for end uses such as car interiors. Preferably,the random velour has a pile height of at least about 2 millimeters.

Any other suitable fiber may also be used in the lofty nonwoven layer100 in addition to the primary fibers 110 and optional binder fibersdescribed previously. These may include, but are not limited to, anadditional binder fiber having a different denier, staple length, crimp,cross-sectional shape, composition, or melting point or a bulking fiberhaving a different denier, staple length, or composition, or a fireresistant or fire retardant fiber. The fiber may also be an effectfiber, providing a desired aesthetic or function. These effect fibersmay be used to impart color, chemical resistance (such as polyphenylenesulfide fibers and polytetrafluoroethylene fibers), moisture resistance(such as polytetrafluoroethylene fibers and topically treated polymerfibers), heat resistance (such as glass or ceramic fibers), fireresistance, or others.

In one embodiment, the nonwoven layer 100 contains fire resistantfibers. These fire resistant fibers may also act as the bulking fibersor may be used in addition to the bulking fibers. As used herein, fireretardant fibers shall mean fibers having a Limiting Oxygen Index (LOI)value of 20.95 or greater, as determined by ISO 4589-1. Types of fireretardant fibers include, but are not limited to, fire suppressantfibers and combustion resistant fibers. Fire suppressant fibers arefibers that meet the LOI by consuming in a manner that tends to suppressthe heat source. In one method of suppressing a fire, the firesuppressant fiber emits a gaseous product during consumption, such as ahalogenated gas. Examples of fiber suppressant fibers includemodacrylic, PVC, fibers with a halogenated topical treatment, and thelike. Combustion resistant fibers are fibers that meet the LOI byresisting consumption when exposed to heat. Examples of combustionresistant fibers include silica impregnated rayon such as rayon soldunder the mark VISIL®, partially oxidized polyacrylonitrile, polyaramid,para-aramid, carbon, meta-aramid, melamine and the like.

Some or all of the fibers (primary 110, optional binder, additionalfibers) may additionally contain additives. Suitable additives include,but are not limited to, fillers, stabilizers, plasticizers, tackifiers,flow control agents, cure rate retarders, adhesion promoters (forexample, silanes and titanates), adjuvants, impact modifiers, expandablemicrospheres, thermally conductive particles, electrically conductiveparticles, silica, glass, clay, talc, pigments, colorants, glass beadsor bubbles, antioxidants, optical brighteners, antimicrobial agents,surfactants, fire retardants, and fluoropolymers. One or more of theabove-described additives may be used to reduce the weight and/or costof the resulting fiber and layer, adjust viscosity, or modify thethermal properties of the fiber or confer a range of physical propertiesderived from the physical property activity of the additive includingelectrical, optical, density-related, liquid barrier or adhesive tackrelated properties.

The network of fibers in the lofty nonwoven layer interact throughentanglement and bonding to provide integrity, strength, and resiliencywhen the lofty nonwoven is exposed to forces. In the planar direction ofthe lofty nonwoven, the degree of entanglement and bonding can bemeasured by the tensile properties of the nonwoven layer.

Another characteristic of the lofty nonwoven layer is the tendency forthe material to deform in the Z-direction when a compression force isapplied and recover its original shape after the compression force isremoved. Preferably, the volumetric porosity of the lofty nonwoven layeris greater than about 50%, more preferably greater than about 80%. Theselevels of porosity in lofty nonwovens will enable Z-directioncompression and recovery properties well suited for many applicationssuch as floor underlayment, carpet padding, and furnishings. Differentlofty nonwoven layers with different combinations of non-uniform fiberorientations, fiber contact points, discrete bond points, and bulkdensities results in materials that exhibit different levels ofcompression and recovery behavior when exposed to Z-directioncompression forces. For example, a loosely connected network of lowstiffness or small diameter fiber may have a very low compressionresistance and compression recovery while a more densely connectednetwork of stiff fibers may offer higher compression resistance andrecovery. These compression and recovery properties may play a criticalrole in how the material behaves when exposed to further processingsteps such as coating, lamination, heating and molding.

The lofty nonwoven layer may also be formed with a non-uniformdistribution of fiber types through the lofty nonwoven layer thickness.One embodiment is a stratified lofty nonwoven layer with one sidecontaining primarily large denier fibers and a second side containingprimarily small denier fibers. Another embodiment is a structurednonwoven with a first face side and a second back side. In thisembodiment the face side is characterized by loops or fiber tuftswherein the fiber axis is generally oriented about in the Z-directionwhile the back side contains similar or dissimilar fibers where thegeneral orientation is about in the planar direction of the nonwovenlayer. An example of one such embodiment would be the nonwoven carpetscommonly used in automotive floors which often comprise a face and aback side.

After the lofty nonwoven layer 100 is formed, a thermoplastic isobtained that will be used to form the film 200. The film 200 may be anysuitable thermoplastic film that contains a thermoplastic polymer. Asuitable polymer is one that has a softening point or melting point nearor sufficiently below the melting or softening point of the polymer usedto make the primary fibers in the lofty nonwoven layer so that theprimary fibers in the lofty nonwoven do not melt or shrink excessivelywhen the thermoplastic polymer is applied to it through heat and/orpressure or when the part is optionally heated to soften thethermoplastic layer as often occurs when molding the nonwoven composite.In one embodiment, for a lofty nonwoven of predominately polyethyleneterephthalate (polyester or (PET)) fibers, low density polyethylene orLDPE is a suitable choice of thermoplastic polymer for the film 200. Thethermoplastic polymer can include but is not limited to polyethylene,polypropylene, polybutylene, polyvinyl chloride, poly (ethylene-co-vinylacetate), nylon, polyethylene terephthalate, polybutylene terephthalate.Also suitable for the thermoplastic polymer would be the general classof thermoplastic elastomers, thermoplastic vulcanizates, thermoplasticpolyurethane, and copolymers or blends of any thermoplastic polymer(s)with processing aids, viscosity modifiers, fillers, density modifyingagents, blowing agents, IR active materials, adhesion modifiers,stabilizers or other additives.

To form the nonwoven composite (10), the thermoplastic polymer isapplied to the second side 100 b of the nonwoven layer 100 in the formof a molten polymer, semi-molten polymer, or solid film. Pressure (andoptionally heat) is applied to the nonwoven substrate and thermoplasticpolymer and the thermoplastic polymer and the second side 100 b of thenonwoven layer 100 are subjected to a textured surface that in oneembodiment form a plurality of peak regions 13 and a plurality of valleyregions 11 in the second side 100 b of the nonwoven layer 100. The highpoints of the textured surface correspond to the valley regions in thenonwoven composite, while the low points of the textured surfacecorrespond to the peak regions of the nonwoven composite. Therefore, thetextured surface has an inverse profile from the desired texture of thenonwoven layer. Application of the pressure and optionally heat occursas the thermoplastic polymer is being applied to the nonwoven layer 100or after the thermoplastic polymer is applied. The thermoplastic film200 and nonwoven layer 100 are then cooled such that the thermoplasticfilm has at least partially solidified. This cooling preferably happenswhile the film is in contact with the textured surface as to preservethe texture in the composite 10. In one embodiment, the application ofthermoplastic polymer and subjecting the film and nonwoven layers topressure (and optionally heat) takes place approximately simultaneously.In another embodiment, the application of thermoplastic polymer andsubjecting the film and nonwoven layers to pressure (and optionallyheat), and then cooling the film takes place approximatelysimultaneously.

One preferred method of applying the thermoplastic to the nonwoven layerand subjecting the combination to the textured surface is by bringingthe nonwoven layer 100 into a nip (which would contain a patternedroller having a textured surface and a pressure roller) and extrudingmolten thermoplastic polymer either onto the nonwoven layer before itenters the nip, onto the nonwoven layer right at the nip, or onto thetextured roller close to the nip. The patterned roller would have atexture of a plurality of valley regions and a plurality of peak regions(the inverse of the desired pattern on the composite). Typically, thetextured roller would be chilled (by cooling water or the like) suchthat the thermoplastic polymer at least partially solidifies into thenegative of the textured surface of the roller before the now coatednonwoven layer leaves the nip.

In another embodiment, the thermoplastic is applied to the nonwoven as afree standing, solid film. This film may be placed on the nonwoven layerand then heat and pressure are applied via a textured surface such thatthe film is at least partially melted and conforms to the texturedsurface. The composite is then cooled preferably while the film is incontact with the textured surface as to preserve the texture in thecomposite 10.

The step of using pressure (and optionally heat) while being subjectedto the textured surface creates the plurality of peak regions 13 andplurality of valley regions 11 in the composite 10. The peak regions 13are identified by the planar portions of the composite surface 10 bcorresponding to the areas of maximum nonwoven composite thickness. Thevalley regions are identified by the planar portions of the compositesurface 10 b where the nonwoven composite thickness is reduced. Themeasured difference in nonwoven composite thickness between the peak andvalley regions is referred to as the indentation depth. The maximumindentation depth measured in the valley region is greater than theaverage film thickness measured in the peak region. Preferably, themaximum indentation depth is greater than 3 times the film thickness.

Being subjected to the textured surface under pressure (and optionallyheat) causes a majority of the film within the valley regions 11 toinfuse into the lofty nonwoven layer 100 and therefore a portion of thefibers 110 become embedded and encapsulated in the film. If a fibercross section is fully surrounded by film it is considered encapsulated.For a given cross section of the composite, preferably greater thanabout 8% of the cross sectional area of the film in the valley region isoccupied by encapsulated fibers of the lofty nonwoven (these fibersinclude all of the fibers of the nonwoven layer including primary fibersand any other fibers included in the nonwoven layer), preferably greaterthan about 10%, more preferably greater than about 15%, more preferablygreater than about 20%.

Preferably, the peak regions comprise essentially no encapsulated fibers(these fibers include all of the fibers of the nonwoven layer includingprimary fibers and any other fibers included in the nonwoven layer) fromthe lofty nonwoven. “Essentially no encapsulated fibers” in thisapplication is defined to mean less than 5% of the cross sectional areaof the film contains encapsulated fibers. This encapsulation of fibersin the valley regions and not in the peak regions can be seen, forexample, in the micrograph of FIG. 2.

In FIG. 2, the area fraction of total fibers in the thermoplastic film(200) within the valley region is shown to be approximately 25% (25%equals 0.25 as a fraction). The area within the lofty nonwoven layernear the second side of the nonwoven layer in the valley region is shownto be locally compressed (distance between fibers is less) relative tothe area within the lofty nonwoven layer in the peak region near thesecond side of the lofty nonwoven layer. When compressed in thickness,lofty nonwoven layers will typically exert a restoring force which actsto restore the material thickness. In the example shown, the localcompression of the lofty nonwoven layer is maintained by the presence ofthe infused and solidified film. This local compression within the loftynonwoven layer implies there are residual stresses within the loftynonwoven layer.

In one embodiment, the angle formed from the plane of the texturedroller and the tangent to the projection from the plane of the belt thatconstitutes the pattern should preferable be between 90° and 120°. Thepercentage of the valley and peak areas can be used to tailor theoverall porosity of the resultant composite.

Preferably, the plurality of valley regions 11 and plurality of peakregions 13 are in a pattern. The pattern may be continuous ordiscontinuous, regular and repeating or random. “Continuous” in thisapplication means that from one edge of the composite to the other edgethere is a continuous path of either peaks or valleys. Some continuouspatterns include linear stripes, grids, a rectilinear grid, and wavylines. “Discontinuous” in this application means that from one edge ofthe composite to the other edge there is not a path of either peaks orvalleys. Examples of discontinuous patterns include dots, most indicia,text, and short random lines. Preferably, the presence of the peakregions and valley regions on the lower surface 10 b of the composite 10is not visibly evident when looking at the upper surface 10 a of thecomposite 10.

In one embodiment, the second side of the nonwoven layer preferablycontains a plurality of wall regions located between the valley regionsand peak regions. Between the peak regions 13 and the valley regions 11will typically be a wall region which is a transitional region betweenthe peaks and the valleys. The wall region may contain physicalcharacteristics of both the peak and valley regions. The maximum slopeor angle of the walls should be at least about 20 degrees, preferablygreater than about 30 degrees, and more preferably greater than about 45degrees relative to the plane of the lower surface of the nonwovencomposite.

The valley region of the film can range from about 5% to 80% of thetotal area of the lower surface 10 b of the composite 10, preferablybetween about 20% and 60%. In a preferred embodiment, the valleys are atleast three times as wide as the average film thickness. In anotherembodiment, the valleys are at least as wide as half the lofty nonwoven100 thickness. In another embodiment, the valleys are at least threetimes as wide as the average spacing between fibers on the second side100 b of the nonwoven 100. Preferably, the valleys are narrower thanthree times the lofty nonwoven thickness, more preferably narrower thanthe lofty nonwoven thickness.

Once the nonwoven composite is formed, it may be treated to anadditional step of adding heat and optionally pressure. During thissecond treatment, the thermoplastic film 200 softens or melts. Theaddition of heat and optionally pressure along with the softening of thethermoplastic film enables the compressed areas of the nonwoven layer torelax and spring back. The forces that drive the relaxation and springback behavior of the nonwoven layer include residual mechanicalstresses, residual thermal stresses, and polymer shrinkage. The relativemotion among the fibers in the nonwoven layer as it relaxes and springsback exert a shearing action on the thermoplastic film locally betweenand among the encapsulated fibers in the valley region of the nonwovencomposite. In some areas of the valley regions, the shearing actionexerted on the thermoplastic film by the encapsulated fibers issufficient to tear the film and open up pores through the thickness ofthe thermoplastic film.

The concentration of encapsulated fibers in the valley regions driven bythe higher localized pressures of the textured surface leads to higherdegrees of relative motion of encapsulated fibers in and around thevalley regions of the nonwoven composite when exposed to the secondtreatment. By controlling the pattern type, pattern feature sizes, filmthickness, and compression properties of the nonwoven layer, the overalldegree of porosity created in the valley region can be controlled. Asthe peak regions preferably have essentially no encapsulated fibers,there are few to no holes or pores formed in the peak regions. Afterheating, in the peak regions, the film and the nonwoven layer arepreferably still two separate and distinct layers where the interfacewhere the two layers meet being readily visible. After this additionalheating step, the plurality of valley regions has a first porosity andthe plurality of peak regions has a second porosity, where the firstporosity is greater than the second porosity.

FIG. 3 illustrates a cross-section showing the pores 120 that are formedin the composite when subjected to an additional heating cycle. FIGS. 4Aand 4B are photo micrographs of the bottom surface of the composite in avalley region. FIG. 4A shows the fibers encapsulated with the film withessentially no holes or pores after the composite has been formed. FIG.4B shows the fibers encapsulated within the film with a plurality holesor pores after the composite has been subjected to the additional heatcycle. FIG. 5 shows a micrograph of a cross-section in a valley regionafter the composite has been subjected to the additional heat cycle,where pores have formed in the film. Note that polymer tends to bridgethe gaps between fibers, creating pores that are smaller than theoriginal windows in the nonwoven fiber bed.

The pores 120 formed after the composite 10 is heated to form composite20 are typically smaller than 0.5 mm along their largest dimension, morepreferably smaller than 0.2 mm. In one embodiment, the number averagepore size is under 0.06 mm and half of the pore area is provided bypores with less than 0.120 mm diameter. The average pore size is relatedto the average distance between fibers in the lofty nonwoven and thedegree of relative motion that occurs between encapsulated fibers duringthe second heating step. Pores 120 with dimensions on this scale areknown to provide excellent sound absorption due to their ability todissipate sound energy in a viscous boundary layer as the sound pressurewaves move air through the pores. Pores of these dimensions can bedifficult to form through common means such as mechanical perforation.

A patterned surface of peaks and valleys wherein the valley regions havegreater porosity than the peak regions has numerous benefits. The solidfilm nature of the peak regions provides an accessible area for bondingof additional layers to the composite without disturbing the porositycreated in the valley regions of the composite and the film of the peakregions, when heated, can act as the adhesive material. In terms ofacoustic performance, the peak regions act primarily as barrier regionswhile the valley regions are highly sound absorbing. The combination ofpeaks and valleys enables a more drapable composite that can be moldedwith fewer wrinkles.

In one embodiment, during this additional heating (with optionalpressure step), the composite 10 is molded into a three-dimensionalshape. Once cooled, the composite will typically retain its molded shapeand be stiff enough not to collapse under its own weight. The moldedcomposite can be used for any suitable application such as moldedacoustic parts for automotive applications.

In one embodiment, a porous absorbing nonwoven layer is attached to thecomposite (preferably on the lower surface of the composite 10. Thisporous absorbing nonwoven layer has a thickness greater than thethickness of the nonwoven layer 100. This porous absorbing nonwovenlayer is sometimes referred to in the automotive industry as a soundabsorbing or shoddy layer. The shoddy layer can be added to a compositeto provide additional acoustic absorption, barrier properties, orvibrational damping properties to the total system, leading to betteroverall performance. The porous absorbing nonwoven layer can be attachedby any suitable means such as adhesive or fasteners. In a differentembodiment, the shoddy can serve as the lofty nonwoven layer 100.

The nonwoven composite 10 may also contain any additional layers forphysical or aesthetic purposes. Suitable additional layers include, butare not limited to, a nonwoven fabric, a woven fabric, a knitted fabric,a foam layer, a film, a paper layer, an adhesive-backed layer, a foil, amesh, an elastic fabric (i.e., any of the above-described woven, knittedor nonwoven fabrics having elastic properties), an apertured web, anadhesive-backed layer, or any combination thereof. Other suitableadditional layers include, but are not limited to, a color-containinglayer (e.g., a print layer); one or more additional sub-micron fiberlayers having a distinct average fiber diameter and/or physicalcomposition; one or more secondary fine fiber layers for additionalinsulation or acoustic performance (such as a melt-blown web or afiberglass fabric); foams; layers of particles; foil layers; films;decorative fabric layers; membranes (i.e., films with controlledpermeability, such as dialysis membranes, reverse osmosis membranes,etc.); netting; mesh; wiring and tubing networks (i.e., layers of wiresfor conveying electricity or groups of tubes/pipes for conveying variousfluids, such as wiring networks for heating blankets, and tubingnetworks for coolant flow through cooling blankets); or a combinationthereof. The additional layers may be on either or both sides of thenonwoven composite. For example, a textile may be applied to one side ofthe nonwoven composite using an optional adhesive layer to form anaesthetic surface for an end use such as certain automobileapplications.

The nonwoven composite 10 may further comprise one or more attachmentdevices to enable the composite 10 to be attached to a substrate orother surface. In addition to adhesives, other attachment devices may beused such as mechanical fasteners like screws, nails, clips, staples,stitching, thread, hook and loop materials, etc.

The one or more attachment devices may be used to attach the composite10 to a variety of substrates. Exemplary substrates include, but are notlimited to, a vehicle component; an interior of a vehicle (i.e., thepassenger compartment, the motor compartment, the trunk, etc.); a wallof a building (i.e., interior wall surface or exterior wall surface); aceiling of a building (i.e., interior ceiling surface or exteriorceiling surface); a building material for forming a wall or ceiling of abuilding (e.g., a ceiling tile, wood component, gypsum board, etc.); aroom partition; a metal sheet; a glass substrate; a door; a window; amachinery component; an appliance component (i.e., interior appliancesurface or exterior appliance surface); a surface of a pipe or hose; acomputer or electronic component; a sound recording or reproductiondevice; a housing or case for an appliance, computer, etc.

EXAMPLES Example 1

The lofty nonwoven of Example 1 was formed from the following fibers:

-   -   95% by weight 9 denier PET fibers with an average staple length        of 76 mm    -   5% by weight 4 denier bicomponent PET binder fibers with an        average staple length of 51 mm (acted as a binder fiber)

The fibers were formed into the lofty nonwoven by a typical carding,crosslapping, and needlepunching operation and then subjected to arandom velour operation to structure the fibers. The weight of the loftynonwoven was 560 g/m².

The second side of the lofty nonwoven was coated with 100 g/m² of 12melt flow rate (MFR) low density polyethylene (LDPE) using a standardextrusion lamination process.

The lofty nonwoven was roll fed into a nip formed by a textured chillroller and a pressure roller such that the second side of the nonwovenfaced the textured chill roller and the first side faced the pressureroller. The molten LDPE was applied to the second side of the nonwovenat the nip.

The textured chill roll texture was formed by cloaking a stainless steelchill roll with a woven fiberglass belt coated with Teflon. The beltexhibited a 5-mm square grid using approximately 840-micron diameteryarns. The yarns of the grid formed approximately 31% of the surfacearea on the roller, with the remaining 69% being open.

An inverse texture of the chill roll was imparted to the second side ofthe nonwoven of Example 1, where the yarn area of the textured chillroll approximately corresponded to the valley regions in the nonwovencomposite and the open area of the belt approximately corresponded tothe peak areas of the nonwoven composite. In the peak regions, the filmhad an average thickness of 0.1 mm and had essentially no fibersencapsulated in it. In the valley regions, the film was embedded intothe lofty nonwoven to a depth equivalent to at least three fiberdiameters and the lofty nonwoven exhibited an indentation depth of about0.47 mm.

Example 2

The nonwoven composite of Example 1 was heated by an infrared heater toa surface temperature of approximately 350° F. while constrained by aframe around all 4 sides, then cooled to near room temperature beforeremoving from the frame. After the heating and cooling, the nonwovencomposite exhibited a plurality of micropores, where the areal porosity(percent of the film area open to the nonwoven substrate below) in thevalleys was greater than 7% and the porosity in the peak regions wasessentially zero, meaning no pores were found in the peak regions overthe area surveyed.

After heating, the peak regions look substantially unchanged from theunheated Example 1, that is, there were essentially no encapsulatedfibers in the film and there are still two separate and distinct layerswhere the interface where the two layers meet being readily visible. Theaverage film thickness in the peak region remained 0.1 mm. The valleyregions of Example 2 exhibit an indentation depth of about 0.100-0.150mm resulting from the decompression of the fibers in the valley regionupon heating. The cross-sectional area fraction of total fibers in thefilm within the valley regions was greater than 15%.

Example 3

The lofty nonwoven of Example 3 was formed from the followingcombination of fibers:

-   -   92% by weight 6 denier PET fibers with an average staple length        of 76 mm    -   8% by weight 4 denier bicomponent PET binder fibers with an        average staple length of 51 mm

The fibers were formed into the lofty nonwoven by a typical carding,crosslapping, and needlepunching operation and then subjected to arandom velour operation to structure the fibers. The weight of the loftynonwoven was 350 g/m².

The second side of the lofty nonwoven was coated with 100 g/m² of 12 MFRLDPE using a standard extrusion lamination process.

The loft nonwoven was roll feed into a nip formed by a textured chillroller and a pressure roller such that the second side of the nonwovenwas facing the textured chill roller and the first side was facing thepressure roller. The molten LDPE was applied to the second side of thenonwoven at the nip.

The textured chill roll texture was formed by cloaking a stainless steelchill roll with a woven fiberglass belt coated with Teflon. The beltexhibited a 5-mm square grid using approximately 840-micron diameteryarns. The yarns of the grid formed approximately 31% of the surfacearea on the roller, with the remaining 69% being open.

An inverse texture of the chill roll was imparted to the second side ofthe nonwoven. Where the yarn area of the textured chill rollapproximately corresponded to the valley regions in the nonwovencomposite and the open area of the belt approximately corresponded tothe peak areas of the nonwoven composite. In the peak regions, the filmhad an average thickness of 0.1 mm and had essentially no fibersencapsulated in it. In the valley regions, the film was embedded intothe lofty nonwoven to a depth equivalent to at least three fiberdiameters and the lofty nonwoven exhibited an indentation depth of about0.47 mm.

Example 4

The nonwoven composite of Example 3 was heated in an oven set to 374° F.on a pin frame, removed from the oven, and cooled to room temperature.After the heating for 1 min, 2 min, or 4 min, and then cooling to roomtemperature, the peak regions look substantially unchanged from theunheated Example 3, that is, there were essentially no encapsulatedfibers in the film and there are still two separate and distinct layerswhere the interface where the two layers meet being readily visible. Theaverage film thickness in the peak region remained 0.1 mm after heating.The nonwoven composite exhibited a plurality micropores, where theporosity in the valley regions was greater than the porosity in the peakregions and the porosity in the peak regions of the nonwoven compositewas essentially zero, meaning no pores were found in the peak regionsover the area surveyed. The valley regions of Example 2 exhibited areduced indentation depth relative to the unheated Example 3.

Example 5

The lofty nonwoven of Example 5 was formed from the following fibers:

-   -   95% by weight 9 denier PET fibers with an average staple length        of 76 mm    -   5% by weight 4 denier bicomponent PET binder fibers with an        average staple length of 51 mm

The fibers were formed into the lofty nonwoven by a typical carding,crosslapping, and needlepunching operation and then was subjected to arandom velour operation to structure the fibers. The weight of the loftynonwoven was 560 g/m².

The second side of the lofty nonwoven was coated with 100 g/m² of 12 MFRLDPE using a standard extrusion lamination process.

The loft nonwoven was roll feed into a nip formed by a textured chillroller and a pressure roller such that the second side of the nonwovenwas facing the textured chill roller and the first side was facing thepressure roller. The molten LDPE was applied to the second side of thenonwoven at the nip.

The chill roll texture was achieved by cloaking a stainless steel chillroll with textured rubber mat. The textured rubber mat exhibited apattern of mutually parallel protrusions running parallel to thedirection of travel of the nonwoven layer through the extrusion range.In the cross section, the shape of the protrusions was an equilateraltriangle with a rounded tip. The spacing between the triangularprotrusions was 1 mm and the stripes were 2.2 mm at the base yielding acenter to center distance between the triangular shaped protrusions of3.2 mm. The protrusions projected outward from the plane of the mat to aheight of 1.4 mm. An inverse texture of the textured rubber mat wasimparted to the second side of the nonwoven composite. This resulted inthe valley regions in the nonwoven composite corresponding in locationand shape to the tip of the equilateral triangle protrusions.

Example 6

The nonwoven composite of Example 5 was heated by an infrared heater toa surface temperature of approximately 350° F. while clamped in a frame,then cooled to room temperature. After the heating and cooling, thenonwoven composite exhibited a plurality micropores, where the porosityin the valleys was greater than the porosity in the peak regions of thenonwoven composite, and the porosity in the peak regions was essentiallyzero, meaning no pores were found in the peak regions over the areasurveyed.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

What is claimed is:
 1. A nonwoven composite having an upper surface anda lower surface, the upper surface and the lower surface furtherdefining a composite thickness, wherein the nonwoven compositecomprises: (a) a lofty nonwoven layer comprising a plurality of primaryfibers and having a first side and an opposite second side, the secondside defining a plurality of peak regions and a plurality of valleyregions, the first side and the second side further defining a nonwovenlayer thickness, wherein the first side of the nonwoven layer forms theupper surface of the nonwoven composite; and (b) a film comprising athermoplastic polymer, the film being present on at least a majority ofthe second side of the nonwoven layer and having a film thickness in thepeak regions of the layer, wherein the film has a first porosity in thevalley regions and a second porosity in the peak regions, wherein thefirst porosity is greater than the second porosity, wherein within thevalley regions the film comprises a plurality of encapsulated fibersfrom the nonwoven layer, and wherein the cross-sectional area fractionof total fibers in the film within the valley regions is at least about8% and the cross-sectional area fraction of total fibers in the filmwithin the peak regions is less than about 5%, wherein the compositethickness is greatest in the peak regions in the lofty nonwoven layerand wherein the composite thickness is reduced in the valley regions inthe lofty nonwoven layer.
 2. The nonwoven composite of claim 1, whereinthe peak regions and valley regions are present as a rectilinear grid.3. The nonwoven composite of claim 1, wherein the peak regions andvalley regions are present as linear stripes.
 4. The nonwoven compositeof claim 1, wherein the second side of the nonwoven layer furthercomprises a plurality of wall regions located between the peak regionsand valley regions.
 5. The nonwoven composite of claim 4, wherein theangle of the walls regions is greater than about 30 degrees relative tothe plane of the lower surface of the nonwoven composite.
 6. Thenonwoven composite of claim 1, wherein the film in the peak regionscomprises essentially no pores.
 7. The nonwoven composite of claim 1,wherein the film in the peak regions comprises essentially noencapsulated primary fibers from the nonwoven layer.
 8. The nonwovencomposite of claim 1, wherein the first porosity is at least 1000%greater than the second porosity.
 9. The nonwoven composite of claim 1,wherein the peak regions comprise between about 40 and 80% of thesurface area of the second surface of the nonwoven layer.
 10. Thenonwoven composite of claim 1, wherein the valley regions comprisebetween about 20 and 60% of the surface area of the second surface ofthe nonwoven layer.
 11. The nonwoven composite of claim 1, wherein thefirst surface of the nonwoven layer comprises a false velour.
 12. Thenonwoven composite of claim 1, wherein the average composite thicknessat the peak regions minus the average composite thickness at the valleyregions is greater than the average peak film thickness.
 13. A nonwovencomposite comprising: (a) a lofty nonwoven layer comprising a pluralityof primary fibers and having a first side and an opposite second side,the second side defining a plurality of peak regions and a plurality ofvalley regions, the first side and the second side further defining anonwoven layer thickness; and (b) a film comprising a thermoplasticpolymer and having a film thickness in the peak regions of the layer,the film being present on at least a majority of the second surface ofthe nonwoven layer, wherein within the valley regions the film comprisesa plurality of encapsulated fibers from the nonwoven layer, and whereinthe cross-sectional area fraction of total fibers in the film within thevalley regions is at least about 8% and the cross-sectional areafraction of total fibers in the film within the peak regions is lessthan about 5%, wherein the composite thickness is greatest in the peakregions in the lofty nonwoven layer and wherein the composite thicknessis reduced in the valley regions in the lofty nonwoven layer.
 14. Thenonwoven composite of claim 13, wherein the peak regions and valleyregions are present as a rectilinear grid.
 15. The nonwoven composite ofclaim 13, wherein film thickness is between about 0.04 and 0.3 mm. 16.The nonwoven composite of claim 13, wherein the film in the peak regionscomprises essentially no encapsulated primary fibers from the nonwovenlayer.
 17. The nonwoven composite of claim 13, wherein the peak regionscomprise between about 20 and 95% of the surface area of the secondsurface of the nonwoven layer.
 18. The nonwoven composite of claim 13,wherein the valley regions comprise between about 5 and 60% of thesurface area of the second surface of the nonwoven layer.
 19. Thenonwoven composite of claim 13, wherein the first surface of thenonwoven layer comprises a false velour.
 20. The nonwoven composite ofclaim 13, wherein the average composite thickness at the peak regionsminus the average composite thickness at the valley regions is greaterthan the average peak film thickness.
 21. A nonwoven composite having anupper surface and a lower surface, the upper surface and the lowersurface further defining a composite thickness, wherein the nonwovencomposite comprises: (a) a lofty nonwoven layer comprising a pluralityof primary fibers and having a first side and an opposite second side,the second side defining a plurality of peak regions and a plurality ofvalley regions, the first side and the second side further defining anonwoven layer thickness, wherein the first side of the nonwoven layerforms the upper surface of the nonwoven composite; and (b) a filmcomprising a thermoplastic polymer, the film being present on at least amajority of the second side of the nonwoven layer and having a filmthickness in the peak regions of the layer, wherein the film has a firstporosity in the valley regions and a second porosity in the peakregions, wherein the first porosity is greater than the second porosity,wherein within the valley regions the film comprises a plurality ofencapsulated fibers from the nonwoven layer, and wherein thecross-sectional area fraction of total fibers in the film within thevalley regions is at least about 8% and the cross-sectional areafraction of total fibers in the film within the peak regions is lessthan about 5%, wherein the composite thickness is greatest in the peakregions of the lofty nonwoven layer and wherein the composite thicknessis reduced in the valley regions of the lofty nonwoven layer, andwherein the average composite thickness at the peak regions minus theaverage composite thickness at the valley regions is greater than theaverage peak film thickness.
 22. The nonwoven composite of claim 21,wherein the average composite thickness at the peak regions minus theaverage composite thickness at the valley regions is greater than threetimes the average peak film thickness.
 23. The nonwoven composite ofclaim 21, wherein the film in the peak regions comprises essentially nopores.
 24. The nonwoven composite of claim 21, wherein the film in thepeak regions comprises essentially no encapsulated primary fibers fromthe nonwoven layer.
 25. The nonwoven composite of claim 21, wherein thefirst porosity is at least 1000% greater than the second porosity.